Development of Random Smoothed Particle Hydrodynamics Method for Landslide Risk Assessment

Landslide risk is often quantified as a product of landslide occurrence (or failure) probability and landslide consequence such as the landslide runout distance and volume of sliding mass. Many efforts have been made to estimate failure probability, but few studies focus on the estimation of landslide consequence, especially the landslide runout distance. This is probably due to the difficulty of slope stability analysis methods in simulating the whole process of a landslide (e.g., initiation of landslide, transportation and final deposition of the sliding mass). For example, without considering stress-strain relationship of soils, the factor of safety and critical slip surface obtained from limit equilibrium methods only correspond to initiation of landslide; while finite element/difference methods may suffer from grid distortion problems when simulating large soil deformation during transportation and final deposition of sliding mass during landslide. To properly assess landslide risk, a Monte Carlo simulation (MCS) based method called random smoothed particle hydrodynamics (RSPH) is proposed. In RSPH, random field theory is combined with a particle-based mesh-free numerical method called smoothed particle hydrodynamics (SPH), which can handle complex geometries and large deformation problems. The proposed approach is able to simulate the whole process of a landslide and provide reasonable estimations of both the failure probability and landslide consequence, leading to proper quantification of landslide risk.